In conventional printers and copiers, sheets of paper or other sheet media are pulled from a stack and fed downstream into the print engine components where the desired image is formed on each sheet. The sheets of paper are stacked in a cassette, tray or similar type of paper holder. Many printers and copiers use multiple paper holders. The paper holders may hold different types, sizes or color paper. Each holder may be a cassette assembly that includes paper feed components, such as a feed roller, shaft and gears, or the holder may be simply a paper tray fitted in a plastic housing. Whatever their configuration or function, the paper holders usually have some type of externally visible designator to distinguish between and among the multiple holders. For example, multiple paper holders are often designated by number, 1, 2, 3 etc.
Presently, the paper holder designators are affixed to, stamped in or embossed on each holder. This presents a problem for printers or copiers that can use two or more interchangeable paper holders. For example, some printers such as the one depicted in FIG. 1 use two optional paper cassette/feeder assemblies in addition the two paper trays mounted within the printer housing. The paper trays are designated paper holders number 1 and 2. The optional cassettes are designated paper holders number 3 and 4. Optional cassettes 3 and 4 are interchangeable. One or both of the optional cassettes may be used at any given time. If a fixed number designator is used for each cassette, then two separate cassettes each having a different number designator must be stocked and sold and used in the correct sequence by the customer. This same problem exists for the paper trays designated as paper holders number 1 and 2 if they are also interchangeable with one another. Such designation systems add undesirable costs and handling complexity to printers and copiers that utilize two interchangeable paper holders.